Hello everyone
I work on a general test on the Mobile, and I Utilize a library sencha
You just need a browser to googleChrome to test

So I have some ideas like that, not necessarily good nor bad, but I suggest:
- Count the number of divs whenever you add more or you may get;
- Measure the height of the page with window.innerHeight;
- A mix between the two, measuring the cumulative height of all your divs;
- Etc.

0. Page B makes periodic requests to see if there is a div to be added,
1. you detect that the page A is full,
2. you send the div to the page B